Metal clamp



y 1944- L. A. BURROWS ET AL ,348,

METAL CLAMP Filed June so, 1942 LawtonAz'thurBufl'ows Justin Bunyan L ATTORNEY Patented May 9, 1944 Lawton Arthur Burrows and Justin Bunyan Loe, Woodbury, N. J., assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware Application June 30, 1942, Serial No. 449,124

4 Claims.

This invention relates to metal fasteners for holding sheets together, and more particularly to clamping devices having novel and useful features.

When metal sheets are to be fastened together, as by riveting, it is desirable that they be in approximately the final position previous to the actual riveting operation. This is particularly important where the sheets are not in positions entirely parallel to one another, as for example where one of said sheets is bent into position to meet the other. Under such conditions, it frequently happens that the two sheets are not properly pulled together unless extraordinary precautions are taken. While various clamping devices have been proposed for the temporary securing of such sheets, no wholly satisfactory device for the purpose has been available.

An object of the present invention is a clamping device characterized by simplicity and effectiveness and adapted to hold in position adjacent sheets of material. A further object is a device adapted to secure in the desired position metal sheets which are to be riveted. A still further object is such a device that can be readily inserted into position and readily released yet will grip the sheets firmly. Additional objects will be disclosed as the invention is described more fully hereinafter.

We have found that the foregoing objects are accomplished by the fastener of our invention. This comprises a metal clamping device having an elongated element extending like an arm from said device and bent at substantially right angles to the longitudinal axis of said fastener, said arm being capable of insertion through superposed holes in the sheets to be secured. A projection attached to the device adjacent to the right angled extension to the arm has a flattened surface substantially parallel to said extending arm. In the subsequent description of the device we will refer to the elongated bent element as the arm, and the projection with flattened surface as the foot. While it has been stated that the elongated arm has been bent substantially at right angles to the longitudinal axis of the clamping device, it is not meant that exactly a right angle will be formed by the bent portion. Instead, this angle is intended to indicate the general direction. By suitable arrangement, the jaws of the clamp are loosened or tightened to allow the release or the gripping of the sheets. This may be accomplished by means of a threaded device, whereby the jaws are adjusted to the desired distance apart by a thumbscrew or the like. Likewise, a device may be used in which the gripping effect is secured by the moving of a holding element up against" the lower sheet under the influence of a spring or other pressure exerting element. In one preferred form, a spring mechanism allows the moving apart under applied pressure of the extended arm and the foot, so that the sheets to be secured can be inserted and held between these elements. When the pressure is released, the spring holds the sheets firmly and tightly together.

For the better understanding of our invention, reference is made to the accompanying drawing, which illustrates one embodiment of its design.

Referring generally to the drawing, Fig. l is a vertical elevation of our device, showing its application. Fig. 2 is a similar illustration with the apparatus elements in somewhat different relative positions. Fig. 3 is a cut-away section showing the internal construction more plainly. Fig. 4 is an illustration of the application of our device in the case of non-parallel sheets.

Referring in greater detail to the various figtires in the drawing, l in Fig. 1 represents the elongated element having an arm directed generally at right angles to the longitudinal axis of the clamping device. This elongated element extends into the body of the device and is secured firmly thereto. A foot 2 likewise extends in a direction parallel to the extended arm I and has a flattened surface adapted to be seated against the surface of one of the sheets to be riveted. Preferably this foot 2 is capable of rotating, hence may be pointed in the same direction as arm I, as shown in Fig. 1, or in the opposite direction, as shown in Fig. 2. In practical use, the sheets to be held together, 5 and 6, are inserted between I and 2 and are held there by means of spring 3. The tension on this spring is controlled by means of the screw 4 which is internally threaded at its shank end and receives the threaded portion of I, as shown in Fig. 3.

The clamping device of our invention is intended only for the temporary fastening together of sheets, as for example when two aluminum sheets or sheets of other material are to be riveted together. In such cases, said sheets are placed one on the other, with holes for the rivets in superposed rows. In order to assure the desired final relative positions of the two sheets, it is necessary to secure the sheets at certain spaced holes while riveting is being carried out at the intermediate holes. Even with ordinary clamps in adjacent holes on either side of the one In practice, the elongated arm of our device is inserted through the superposed holes adjacent-- to the hole through which the rivet is to be in-' serted. With the right angled extension arm and the foot both turned towardthe rivet hole,

the sheets are held firmly together. If desired,

clamps may be inserted in the adjacent holes on each side of the rivet perforation. In inserting the clamp, the space between the arm and the foot is increased by pressing down the screw and thereby exerting pressure on the spring. A suitable-tool canbe employed for this purpose, which will hold the clamp-at, 8, while pressure is applied on l. When the pressure is released, the sheets are held tightly.

The clamp may be employed with the arm and foot turned in the same direction or in opposite directions, as shown in Figs. 1 and 2, respectively. Preferably we use. the arrangement shown in Fig. 1, that is with-bothturned in the same direction, as a better clamping efiect is thereby at tained. Consequently, it is desirable that either the arm or foot be capable of rotation, in order thatthe end of thearm canbe inserted through the perforations in the sheets to be riveted. De-. sirably the foot is capa -eof rotation, as we prefer. tohave the arm secured by threading into the base of the screw 6. It should be under, stood, however, that the rotation of neither arm nor foot is necessary, and the device may be made with fixed arm and foot, pointing in opposite directions.

The particular application of our improved device to the clamping of bent sheets or joggles is illustrated in Fig; i, where sheet H has been secured to sheet it? by riveting andit is desired to fasten sheet l2. thereover. In order to accommodate the change in direction at H, itis necessary for sheet it to be bent. With the sheets already riveted at hole l3, it is desired to rivet them next at It. The clamp of our invention is consequently put in place at hole l5, With arm I and foot 2 extending almost to hole M and holding the sheets firmly and flatly together. Riveting may then take place at M. In such a case, it may be desirable also to have a similar clamp inserted through hole H and placed so that the arm and foot project toward hole 56, where anotherrivet may be set in place.

By operating in the foregoing manner, the sheets to be joined are firmly in position prior to the riveting action, with consequent better fitting together.

The clamp of our invention possesses points of superiority over other types of the prior art, as has been pointed out in the foregoing. By its use the complete drawing together of superposed sheets can readily be carried out before the riveting of the sheets, the rivet acting merely to hold the sheets tightly in place. This is a point that is particularly important in positions where access tothe back side is difficult or impossible. It will be understood that our clamp may be constructed of any desired metal or other suitable hard material, preferably steel.

In connection with the drawing, our preferred form of clamp has been shown, wherein the gripping effect is obtained by means of a spring. It will be understood, however, that this clamping eifect may be obtained by any desired means, for example, by means of a screw or otherwise. It is essential in all cases that the combination be present of an extended arm capable of being inserted through the perforated sheet, and a flattened surface adjacent to said arm extension and substantially parallel thereto.

We have disclosed our invention at length in the foregoing. While it has been described particularly'forholding together metal sheets, aluminum, copper, steel and the like, it can be applied equally to the temporary fastening of any type of sheets, cardboard, fiber, asbestos, plastics, and the like. We intend to be limited, therefore, only by the following patent claims.

We claim:

1. A metal clamping device adapted to hold together at least two perforated sheets of material, said device comprising'an element having an elongated arm extending substantially at right angles to the longitudinal axis of saihd device andcapable of being inserted through holes in the sheets to be secured; a projection-attached to said device having a fiat surface adjacent to the extended portion of the arm and likewise extending substantially at right angles to the longitudinal axis of the device to a point substantially outside the normal base of said device; and means for moving apart and drawing together the aforesaid extended arm and flat surface.

2. A metal clamping device adapted to hold together at least two perforated sheets of material, said device comprising an element having an elongated arm extending substantially at right angles to the longitudinal axis of said device and capable of being inserted through holesin the sheets to be secured; a projection attached to said device having a flat surface adjacentto the extended portion of the arm and likewise extending substantially at right angles to the longitudinal axis of the device to a point substantially outside the normalbase of said device; and a spring mechanism allowing the moving apart of the extended arm and the flat surface and the subsequent grippingtogether of the same.

3. The clamping device. of claim 1, in which one of the elements. comprising the extended arm and the fiat projecting surface is capable of rotation.

4. A metal clamping device adapted .to hold together at least two perforated sheets of material, said device comprising an element having an elongated arm extending substantially at right angles to the longitudinal axis of said device and capable of being inserted through holes in the sheets to be secured; a projection attached to said device having a flat surface adjacent to the extended. portion of the arm and likewise extendingsubstantially at right angles to the longitudinal axis of the device to a point substantially outside the normal base of said device, said projection being capable of rotation; and a spring mechanism allowing the moving apart of the extended arm and'the flat surface on application of pressure, and the subsequent drawing together of the same on the release of said pressure, under the influence of the spring,

LAWTON ARTHUR BURROWS. JUSTIN BUNYAN LOE. 

